Fixing apparatus for heat sink

ABSTRACT

A fixing apparatus ( 30 ) for pressing a heat sink ( 70 ) against an electronic device ( 20 ) positioned in a retention module ( 62 ), includes two pressing members ( 32 ) and a fastener ( 52 ). An elongate slot ( 34 ) is defined in a center of each pressing member. Two spring fingers ( 36 ) extend inwardly and downwardly from the pressing member at opposite ends of the slot respectively. An engaging portion ( 42 ) is formed at an end of the pressing member. A locking leg ( 47 ) depends from an opposite end of the pressing member. Two engaging slots ( 54 ) are defined in opposite ends of the fastener for receiving the engaging portion of the pressing member. Two locking legs ( 56 ) depend from opposite ends of the fastener respectively. A hook ( 48, 57 ) is defined at a distal end of each locking leg.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to fixing apparatuses for heat sinks, and particularly to a fixing apparatus which provides uniform pressure distribution.

[0003] 2. Related Art

[0004] With the rapid development of computers, the processing speeds of the processing units of computers have become faster and faster. As a result, a modern processing unit consumes considerable electronic energy and generates much heat. To prevent a processing unit from overheating, it is conventional to install a heat sink pressing against the processing unit. Typically, a fixing apparatus is needed to firmly press the heat sink against the processing unit.

[0005] A conventional fixing apparatus as disclosed in U.S. Pat. No. 5,671,118 is used to press a heat sink against a processing unit. Referring to FIG. 3, a channel 12 is defined in a central portion of the heat sink 10. The fixing apparatus 14 is received in the channel 12. Two engaging portions 24 are provided on opposite ends of a socket 22. The fixing apparatus 14 can engage with the engaging portions 24, and thereby firmly press the heat sink 10 against the processing unit 20.

[0006] However, the fixing apparatus 14 only presses on a middle portion of the heat sink 10. As a result, the pressure distribution is not uniform, and the heat dissipating efficiency of the heat sink 10 is diminished. This is particularly in the case when the heat sink 10 is large. In addition, a fan can not be attached onto the fixing apparatus 14 to provide forced ventilation for the heat sink 10.

SUMMARY OF THE INVENTION

[0007] Accordingly, an object of the present invention is to provide a fixing apparatus which provides uniform pressure distribution on a heat sink.

[0008] To achieve the above-mentioned object, a fixing apparatus in accordance with a preferred embodiment of the present invention is for pressing a heat sink against an electronic device positioned in a retention module, includes two pressing members and a fastener. An elongate slot is defined in a center of each pressing member. Two spring fingers extend inwardly and downwardly from the pressing member at opposite ends of the slot respectively. An engaging portion is formed at an end of the pressing member. A locking leg depends from an opposite end of the pressing member. Two engaging slots are defined in opposite ends of the fastener for receiving the engaging portion of the pressing member. Two locking legs depend from opposite ends of the fastener respectively. A hook is defined at a distal end of each locking leg.

[0009] Other objects, advantages and novel features of the present invention will be drawn from the following detailed description of the preferred embodiment of the present invention with attached drawings, in which:

BRIEF DESCRIPTION OF THE DRAWINGS

[0010]FIG. 1 is an exploded, isometric view of a fixing apparatus in accordance with the preferred embodiment of the present invention, together with a fan, a heat sink, a retention module, a processing unit, and a circuit board;

[0011]FIG. 2 is an assembled view of FIG. 1; and

[0012]FIG. 3 is an exploded, isometric view of a conventional fixing apparatus, together with a heat sink, a processing unit and a socket.

DESCRIPTION OF THE PREFERRED EMBODIMENT

[0013] Referring to FIGS. 1-2, the present invention will be described in its preferred embodiment in conjunction with a rotary fan 80, a heat sink 70, a retention module 62, a processing unit 20, and a circuit board 60. A fixing apparatus 30 in accordance with the preferred embodiment of the present invention is engaged with the retention module 62, for pressing the heat sink 70 against the processing unit 20. Additionally, the fan 80 can be attached onto the fixing apparatus 30 for increasing an efficiency of heat removal.

[0014] The processing unit 20 is located in a center of the retention module 62. Four locking columns 64 extend upwardly from four corners of the retention module 62 respectively. A locking hole 66 is defined in each locking column 64. Four fixing columns 68 depend from four corners of the retention module 62 respectively, for fixing the retention module 62 to the circuit board 60. The heat sink 70 comprises a base 72, and a plurality of parallel fins 74 extend upwardly from the base 72.

[0015] The fixing apparatus 30 comprises two elongate pressing members 32 and an elongate fastener 52. An elongate slot 34 is defined in a center of each pressing member 32. Two spring fingers 36 extend respectively inwardly and downwardly from the pressing member 32 at opposite ends of the slot 34, for resiliently pressing the heat sink 70. Two fixing holes 38 are defined in the pressing member 32 near the opposite ends of the slot 34 respectively. An engaging portion 42 is formed at an end of the pressing member 32. An opening 44 is longitudinally defined in a center of the engaging portion 42, for providing resiliency for the engaging portion 42. Two locking grooves 46 are defined in opposite lateral edges of the engaging portion 42 respectively. A locking leg 47 depends from an opposite end of the pressing member 32. A hook 48 is formed at a distal end of the locking leg 47, for engaging in a corresponding locking hole 66 of the retention module 62. The pressing member 32 has a concave inner edge near the slot 34, the edge corresponding to a passage of airflow from the fan 80.

[0016] The fastener 52 defines two spaced, aligned engaging slots 54 in opposite ends thereof respectively, for engagingly receiving the engaging portions 42 of the pressing members 32 respectively. Two locking legs 56 depend from opposite ends of the fastener 52 respectively. A hook 57 is formed at a distal end of each locking leg 56, for engaging in a corresponding locking hole 66 of the retention module 62. An operating portion 59 is bent outwardly from a top edge portion of the fastener 52.

[0017] In assembly of the fixing apparatus 30, the engaging portions 42 of the pressing members 32 are inserted into the engaging slots 54 of the fastener 52. The engaging portions 42 are resiliently compressed as they pass through the engaging slots 54, and then resiliently snap back to their original shapes. In this position, the engaging portions 42 are firmly engaged in the engaging slots 54. Opposite edge portions of the fastener 52 at each engaging slot 54 are engaged in the locking grooves 46 of the corresponding engaging portion 42.

[0018] In assembly of the fixing apparatus 30 to the heat sink 70, the fixing apparatus 30 is placed onto the heat sink 70. The hooks 48 of the pressing members 32 are engaged in the corresponding locking holes 66 of the retention module 62. The operating portion 59 is depressed, so that the hooks 57 of the fastener 52 engage in the corresponding locking holes 66 of the retention module 62. The spring fingers 36 of the fixing apparatus 30 resiliently depress opposite sides of the heat sink 70 respectively, thereby applying uniform pressure on the heat sink 70. Four screws 82 are extended through the fan 80 and engaged in the fixing holes 38 of the pressing members 32, thereby fixing the fan 80 onto the fixing apparatus 30.

[0019] It is understood that the invention may be embodied in other forms without departing from the spirit thereof. Thus, the present example and embodiment is to be considered in all respects as illustrative and not restrictive, and the invention is not to be limited to the details given herein. 

What is claimed is:
 1. A fixing apparatus for pressing a heat sink against a processing unit, the fixing apparatus comprising: two pressing members, each of the pressing members defining a slot therein and forming at least one finger extending from a periphery of the slot for pressing the heat sink, an engaging portion formed at an end of each of the pressing members, a locking leg depending from an opposite end of each of the pressing members; and a fastener defining two spaced engaging slots engagingly receiving the engaging portions of the pressing members, the fastener having two locking legs depending from opposite ends thereof respectively.
 2. The fixing apparatus as described in claim 1, wherein two fixing holes are defined in each of the pressing members near opposite ends of the slot respectively.
 3. The fixing apparatus as described in claim 1, wherein each of the pressing members has a concave inner edge.
 4. The fixing apparatus as described in claim 1, wherein an operating portion is bent outwardly from a top edge portion of the fastener.
 5. The fixing apparatus as described in claim 1, wherein an opening is longitudinally defined in the engaging portion.
 6. The fixing apparatus as described in claim 5, wherein two locking grooves are defined in opposite lateral edges of the engaging portion respectively, for engagingly receiving the fastener at a corresponding engaging slot.
 7. The fixing apparatus as described in claim 1, wherein each of the pressing members forms two fingers, which extend respectively inwardly and downwardly from the pressing member at opposite ends of the slot.
 8. The fixing apparatus as described in claim 1, wherein a hook is formed on each of the locking legs.
 9. A heat sink assembly comprising: a circuit board; a retention module surrounding a processing unit mounted on the circuit board; a heat sink attached to the processing unit; and a fixing apparatus fixing the heat sink against the processing unit, the fixing apparatus comprising a pair of spaced pressing members and a fastener connecting the pressing members at respective ends thereof, at least one finger extending from each of the pressing members and resiliently pressing the heat sink toward the processing unit, four locking legs respectively depending from opposite sides of the fixing apparatus and interlocking with the retention module.
 10. The heat sink assembly as described in claim 9, wherein four locking columns extend upwardly from four corners of the retention module, and each of the locking columns defines a locking hole therein.
 11. The heat sink assembly as described in claim 9, wherein a slot is defined in a central portion of each of the pressing members.
 12. The heat sink assembly as described in claim 11, wherein two fingers extend from each of the pressing members, the fingers extending inwardly and downwardly from the pressing member at opposite ends of the slot respectively.
 13. The heat sink assembly as described in claim 1, wherein two fixing holes are defined in the pressing member near opposite ends of the slot respectively.
 14. The heat sink assembly as described in claim 9, wherein an operating portion is bent outwardly from a top edge portion of the fastener.
 15. The heat sink assembly as described in claim 9, wherein an engaging portion is formed at an end of each of the pressing members.
 16. The heat sink assembly as described in claim 15, wherein an opening is longitudinally defined in the engaging portion.
 17. The heat sink assembly as described in claim 15, wherein the fastener defines two spaced engaging slots, the engaging slots corresponding to the engaging portions of the pressing members.
 18. The heat sink assembly as described in claim 17, wherein two locking grooves are defined in respective opposite lateral edges of each of the engaging portions, the locking grooves engagingly receiving the fastener at a corresponding engaging slot.
 19. The heat sink assembly as described in claim 9, wherein said pair of pressing members are only pivotally linked to said fastener, respectively, without other connection means therebetween.
 20. A heat sink assembly comprising: a heat sink stacked upon an electronic package and defining laterally opposite first and second sides thereof; a retention module having portions circumferentially positioned beside said electronic package; a fixing apparatus defining an elongated member laterally extending across said heat sink from the first side to the second side, a first leg extending downwardly from one end of the elongated member on said first side and a second leg extending downwardly from the other end of the elongated member on said second side, both said first and second legs being locked to the retention module; said elongated member including spring fingers downwardly biasing the heat sink against the electronic package, and a fixing device; and a fan supportably located on said fixing apparatus and secured to said fixing device. 